Tsuda Akihiko, Ozawa Naoko, Muranaka Ryo, Kuwahara Tomoya, Matsune Ayako, Liang Fengying
Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan.
ACS Omega. 2023 Jul 18;8(30):27802-27810. doi: 10.1021/acsomega.3c04290. eCollection 2023 Aug 1.
Here, we report a novel photo-on-demand phosgenation reaction that crosses three phases of a heterogeneous solution of chloroform (CHCl) and aqueous NaOH containing an aryl alcohol or amine. This reaction system enables the safe, convenient, and inexpensive synthesis of carbonate esters, polycarbonates, and N-substituted ureas from aryl alcohols, aryl diols, and primary/secondary amines, respectively, on a practical scale and with good yield. The photochemical oxidation of CHCl to phosgene (COCl) occurs upon irradiation with UV light from a low-pressure mercury lamp of both the gas and liquid phases of the reaction system under O bubbling of the vigorously stirred sample solution. The following reaction mechanisms are suggested: The aryl alcohol reacts with the generated COCl at the interfaces of the organic/aqueous phases and aqueous/gas phases, in competition with the decomposition of COCl due to hydrolysis. Nucleophilicity and hydrophilicity are enhanced by the formation of aryl alkoxide ion through the reaction with NaOH, whereas the reaction of amine proceeds through neutralization of the generated HCl by the aqueous NaOH.
在此，我们报道了一种新型的光控光气化反应，该反应跨越了含有芳醇或胺的氯仿（CHCl）与氢氧化钠水溶液的非均相溶液的三相。该反应体系能够分别从芳醇、芳二醇和伯/仲胺以实际规模且高收率安全、方便且廉价地合成碳酸酯、聚碳酸酯和N-取代脲。在用低压汞灯的紫外光照射时，在剧烈搅拌的样品溶液的O鼓泡下，反应体系的气相和液相中的CHCl光化学氧化生成光气（COCl）。提出了以下反应机理：芳醇在有机/水相和水/气相的界面处与生成的COCl反应，同时存在COCl因水解而分解的竞争反应。通过与NaOH反应形成芳醇盐离子可增强亲核性和亲水性，而胺的反应则通过NaOH水溶液中和生成的HCl来进行。
